package com.hxl.servlet;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.URLEncoder;

public class FileServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        //1. 要获取下载文件的路径
        //String realPath = this.getServletContext().getRealPath("/1.jpg");
        String realPath = "D:\\aAAAA\\javaweb\\javaweb-02-servlet\\response\\src\\main\\resources\\1.jpg";
        System.out.println("下载文件的路径："+realPath);
        //2. 下载的文件名是？
        String fileName = realPath.substring(realPath.lastIndexOf("\\") + 1);
        //3. 设置让浏览器能够支持(Content-disposition)下我们需要的东西
        resp.setHeader("Content-disposition","attachment;filename="+fileName);
        //resp.setHeader("Content-disposition","attachment;filename="+ URLEncoder.encode(fileName,"UTF-8"));
        //4. 获取下载文件的输入流
        FileInputStream in = new FileInputStream(realPath);
        //5. 创建缓冲区
        int len = 0;
        byte[] buffer = new byte[1024];
        //6. 获取OutPutStream对象
        ServletOutputStream out = resp.getOutputStream();
        //7. 将FileOutputStream流写入到buffer缓冲区.使用OutputStream将缓冲区的数据输出到客户端
        while((len = in.read(buffer)) > 0){
            out.write(buffer, 0, len);
        }

        out.close();
        in.close();

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}
